overdue tasks in line graphs

I'm interested in using the line graphs feature to track how many tasks due on a particular day are completed.

When a repeating task (say, one set to repeat daily) is overdue, how is that treated on the line graph? Does it show up in the count of "due tasks" only on the original due date, or also on subsequent days until it's completed? (So if a task is due Sept 20th, and I skip it, will it show up in the due count on the 21st, 22nd, etc, until I complete it?).